Improvement in locks



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UNITED STATES PATENT OFFICE.

W. C. MCGILL, OF CINCINNATI, OHIO.'

IMPROVEMENT IN LOCKS.

Specification forming part of Letters Patent No. 54,383, dated May 1,1866.

To all whom it may concern:

Beit known that I, W. O. IVIGGILL, of Oincinnati, Hamilton county, andState of Ohio, have invented a new and useful Improvement in Locks, ofVwhich thefollowing is a full and clear description thereof, referencebeing had to the accompanying drawings, making part of thisspeciication.-

My invention relates to a simple device, coin posed of a plate and tube,which completely covers the key-hole of the lock when the key is in it,preventing it being opened from the out side.

Figure l represents a perspective view of my improved lock, the backplate being removed, showing the arrangement of the interior parts. Fig.2 is a transverse vertical sect-ion taken through the key-hole of thelock.

Ais the body of the lock. a is the back plate, which is secured to thebody ofthe lock A by screws.

B is the bolt, secured either open or shut by means of lock-bar G,look-barO being operated upon by the key previous to the throwing ofbolt B.

Within the lock is the the metal plate D, large enough to cover thekey-hole e, over which it is located.

At opposite extremities are springs d, secured to plate D. These springsbear upon the back plate, a, which causes plate D to remain in contactwith the lbody of the lock A.

b are guide-pins for plate D, and are secured to the body ofthe lock A.

The plate D is perforated opposite the keyhole e, and a freely-slidingtube, E, inserted.

Operation: In lockingthe door on the inside, the key having beeninserted in the keyhole, a slight pressure is sufficient to press plateD against back plate, a, tube E passing out and filling a larger part4of key-hole e. The bolt is then thrown and the door locked, the keybeing in the lock. The plate D is retained in contact with the backplate, a, eii'ectually covering key-hole e, and preventing the pickingof the lock from the outside.

Having described my invention, the use and operation of its variousparts, I make the followingclaims, which I desire to secure by LettersPatentl. The plate D and springs d, operating and constructed as and forthe purpose heretofore described.

2. The plate D, springs d, and tube E, conl structed and operatingsubstantially as above described and for the purpose set forth.

W. G. MGGILL. Attest:

A. J. GIBSON, f WM. DOEGEN.

